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Inspection and Assessment of Crash Test Protocols:

Task 3.1-Task 3.2 Report – Part II (31” ET-Plus System Crash Tests)

Submitted to

Federal Highway Administration

U.S. Department of Transportation

Washington, DC

By

H. Clay Gabler, PhD

Virginia Tech

Blacksburg, VA

On

11 March 2015

Virginia Tech (03-11-2015) 2

Inspection and Assessment of Crash Test Protocols:

Task 3.1-Task 3.2 Report Part II (31” ET-Plus System Crash Tests)

H. Clay Gabler, PhD

Virginia Tech 11 March 2015

Background The goal of this report is to evaluate the performance of the ET-Plus end terminal when tested to the

NCHRP 350 Test Level 3 (TL-3) crash test procedure. In December 2014 and January 2015, Southwest

Research Institute (SWRI) conducted two series of crash tests of the ET-Plus end terminal – (1) a series of

TL-3 tests with the ET-Plus end terminal installed with a 27-3/4” height w-beam guardrail system, and

(2) a series of TL-3 tests with the ET-Plus end terminal installed with a 31” height w-beam guardrail

system.

SWRI conducted four tests of the ET-Plus end terminal at each guardrail height to NCHRP 350 Test Level

3. Together, the 27-3/4” and 31” test series comprised a total of eight (8) crash tests. The test matrix

for each guardrail height is shown in Table 1.

Table 1. ET-Plus Test Matrix – repeated for each guardrail height

NCHRP Test Test Vehicle Impact Speed (km/hr)

Impact Angle

Impact Location

3-30 820C 100 0o Vehicle front offset ¼ vehicle width from vehicle centerline

3-31 2000P 100 0o Vehicle front at centerline

3-32 820C 100 15o Vehicle front at centerline

3-33 2000P 100 15o Vehicle front at centerline

This report provides an analysis of the crash test results for the 31” height w-beam guardrail system as

required by Task 3.1 and Task 3.2 of our FHWA contract. This report is the second of two parts of the

Task 3 analysis. Our February 3, 2015 report presented an evaluation of the results from the 27-3/4”

system crash tests.

Approach The approach was to assess the following crash test results by review of the following:

Test reports, prepared by SWRI (Ferren, 1/2015; Ferren, 2/2015), documenting the results of the

NCHRP 350 3-30, 3-31, 3-32, and 3.33 crash tests


Videos of each test, prepared by SWRI

Electronic data included in the test reports for data quality.

In addition, on December 16-17, 2014, I visited the SWRI crash testing facility in San Antonio, Texas to

inspect and assess the crash test procedures and protocols used to conduct crash tests to the NCHRP

Report 350 procedures for Terminals and Crash Cushions. During this visit, I also witnessed two crash

tests (the 3-31 and 3-32 crash tests) of the ET-Plus end terminal installed for the 27-3/4” rail system. On

January 14-16, 2015, I visited SWRI again to observe the pre-test preparation and the actual conduct of

the 3-31 and 3-33 crash tests of the ET-Plus end terminal installed for the 31” rail system.

The analysis included comparison of the actual test conditions against the NCHRP 350 test conditions

tolerances, and assessment of the test results using the NCHRP 350 evaluation criteria. Inspection of the

electronic data plotted in the crash test report showed that no sensors failed during the test, and all

data from these sensors was suitable for computation of occupant impact velocity and occupant

ridedown acceleration.

Results

Test 3-30, ET-Plus installed with 31” guardrail system

This test involved a 820C vehicle (a 1998 Geo Metro) which impacted an ET-Plus end terminal at a

nominal speed of 100 km/hr at an angle of zero degrees. The impact point on the vehicle front was

offset approximately one-quarter of the vehicle width to the right of the vehicle centerline.

Table 2 shows the actual test conditions as documented in the test report. This table also shows the

deviations from the nominal NCHRP 350 test conditions.

Table 2. Test Conditions for Test 3-30 for 31” system

Test Parameter Test Value Nominal

Value Deviation

Total Mass – vehicle + ballast+ dummy (kg) 883 895 -12

Impact Velocity (km/hr) 102.8 100 2.8

Impact Angle (degrees) 0.2 0 0.2

Impact Severity (KJ) 329.9 316.4 13.5

For this test, the NCHRP 350 preferred tolerance is +/- 4.0 km/hr for impact speed, +/- 25 kg for mass,

and +/- 1.5 degrees for impact angle. The tolerance for impact severity (IS) is -24.8 to 25.8 kJ. The

actual values for vehicle mass, impact speed, impact angle, and impact severity were all within these

tolerance ranges.

Table 3 compares the crash test results with the corresponding NCHRP 350 evaluation criteria. The

intrusion of the door into the occupant compartment was closely examined for the potential of serious

injury. My conclusion is that this test would not be likely to cause serious injury to an occupant exposed


to these crash conditions. Appendix A presents an analysis of the potential for serious injury risk in this

crash test.

Table 3. Test Results for Test 3-30 for 31” system

Test NCHRP 350 Evaluation Criteria Test Result Pass/Fail

Structural Adequacy

C ) Acceptable Test Article Performance may be by redirection, controlled penetration, or controlled stopping of the vehicle

Test article slowed the vehicle in a controlled manner after which the vehicle left the system and yawed to a stop.

Pass

Occupant Risk

D) Detached elements, fragments, or other debris from the test article should not penetrate or show potential for penetrating the occupant compartment or present an undue hazard to other traffic, pedestrians, or personnel in a work zone. Deformations of, or intrusions into, the occupant compartment that could cause serious injuries should not be permitted

Folded rail struck driver door. There was no penetration of the test article into the occupant compartment. However, occupant compartment intrusion was 6.75"

Pass

Occupant Risk

F) The vehicle should remain upright during and after collision although moderate roll, pitching and yawing are acceptable.

Vehicle remained upright throughout the test

Pass

Occupant Risk

H1) Occupant Impact Velocity, Longitudinal (< 9m/s preferred, <=12 m/s max)

OIV=8.2m/s Pass

Occupant Risk

H2) Occupant Impact Velocity, Lateral (<= 9m/s preferred, <=12 m/s max)

OIV=0.4m/s Pass

Occupant Risk

I1) Occupant Ridedown Accel, Longitudinal (< 15 G preferred, <=20 max)

ORA=-11.8G Pass

Occupant Risk

I2) Occupant Ridedown Accel, Lateral (< 15 G preferred, <=20 max)

ORA=8.7G Pass

Vehicle Trajectory

K) After collision, it is preferable that the vehicle's trajectory not intrude into adjacent lanes

Vehicle spun out on traffic side of test article, and potentially into adjacent traffic lane

**

Vehicle Trajectory

N) Vehicle trajectory behind the test article is acceptable

Vehicle remained on traffic side of test article

Pass

** Note that this evaluation criteria is preferred, but not required. Vehicle spinout is typical behavior

for this type of offset test.



This test involved a 2000P vehicle (a 1998 Chevrolet C2500 Pickup truck) which impacted the ET-Plus

end terminal at a nominal speed of 100 km/hr at an angle of zero degrees. The impact point on the

vehicle front was approximately on the vehicle centerline.





Value Deviation

Total Mass – vehicle + ballast (kg) 2023 2000 23

Impact Velocity (km/hr) 103.8 100 3.8


Impact Severity (KJ) 840.7 771.7 69.1


and +/- 1.5 degrees for impact angle. The tolerance for impact severity (IS) is -60.4 kJ to 62.9 kJ. The

actual values for vehicle mass, impact speed, and impact angle were all within these tolerance ranges.

The impact severity exceeded the positive tolerance on impact severity. However, NCHRP 350 (section

3.3.3) states that exceeding the positive tolerance on impact severity is acceptable if all other evaluation

criteria are met. This was the case in this crash test.

Table 5 compares the crash test results with the corresponding NCHRP 350 evaluation criteria. My

conclusion is that the test article passed this test.




Structural Adequacy


Test article stopped the vehicle in a controlled manner.

Pass

Occupant Risk


No intrusion into the occupant compartment

Pass

Occupant Risk



Pass

Occupant Risk


OIV=5.9m/s Pass

Occupant Risk


OIV=0.2 m/s Pass

Occupant Risk


ORA = -8.0G Pass

Occupant Risk


ORA = 7.0 G Pass

Vehicle Trajectory


Test article brought the vehicle to a complete stop while still in contact with the end terminal head.

Pass

Vehicle Trajectory


Vehicle did not travel behind the test article

Pass



This test involved a 820C vehicle (a 1996 Chevrolet/Geo Metro) which impacted the ET-Plus end

terminal at a nominal speed of 100 km/hr at an angle of 15 degrees. The impact point on the vehicle

front was approximately on the vehicle centerline.





Value Deviation

Total Mass – vehicle + ballast+ dummy (kg) 892.4 895 -2.6

Impact Velocity (km/hr) 98.5 100 -1.5


Impact Severity (KJ) 305.9 316.4 -10.5


and +/- 1.5 degrees for impact angle. The tolerance for impact severity (IS) is -24.8 to 25.8 kJ. The

actual values for vehicle mass, impact speed, impact angle, and impact severity were all within these

tolerance ranges.





Structural Adequacy


Test article allowed the vehicle to gate in a controlled manner through the end terminal as designed.

Pass

Occupant Risk


No intrusion into the occupant compartment. There was some tearing of the external sheetmetal of the driver door from contact with the end terminal, but the terminal did not intrude or penetrate into the occupant compartment.

Pass


Occupant Risk



Pass

Occupant Risk


OIV = 7.9m/s Pass

Occupant Risk


OIV =-1.3m/s Pass

Occupant Risk


ORA=-6.4G Pass

Occupant Risk


ORA=6.3G Pass

Vehicle Trajectory


Vehicle gated through the end terminal and travelled behind the test article.

Pass

Vehicle Trajectory



Pass



This test involved a 2000P vehicle (a 1994 GMC C2500 Pickup truck) which impacted the ET-Plus end

terminal at a nominal speed of 100 km/hr at an angle of 15 degrees. The impact point on the vehicle

front was approximately on the vehicle centerline.





Value Deviation

Total Mass – vehicle + ballast (kg) 1981 2000 -19

Impact Velocity (km/hr) 93 100 -7


Impact Severity (KJ) 661.4 771.7 -110.3

NCHRP 350 preferred tolerance for impact speed is +/- 4.0 km/hr, +/- 45 kg for mass, and +/- 1.5 degrees

for impact angle. The tolerance for impact severity (IS) is -60.4 kJ to 62.9 kJ. The actual values for

vehicle mass and impact angle were both within these tolerance ranges. However, the actual value for

impact speed of 93 km/hr was 3 km/hr outside the negative tolerance range specified by NCHRP 350.

Likewise, impact severity, which is a function of impact speed, was outside the negative tolerance range.

We considered two aspects of whether the evaluation of the 31” system would have changed if the

vehicle speed had been 3 km/hr faster (1.8 miles/hour). First, because the end terminal system gated

properly even at this lower speed, it would be expected to break away and gate at a slightly higher

speed. Second, the occupant risk metrics OIV and ORA would be expected to increase slightly with

higher impact speed. However, the OIV and ORA values in the actual 3-33 test were well below the

preferred values. If the test were run at a speed of 3km/hr higher, these occupant risk metrics would

not be expected to exceed either the preferred limits or the maximum limits. In my judgment, the

evaluation of the 31” system would not have changed if the vehicle speed had been 3 km/hr higher.





Structural Adequacy


Test article allowed the vehicle to gate in a controlled manner through the end terminal as designed.

Pass



Occupant Risk


No intrusion into the occupant compartment. There was some contact between the terminal and the side of the truck forward of the driver door which slightly dented the side of the vehicle. The terminal did not however intrude or penetrate into the occupant compartment.

Pass

Occupant Risk



Pass

Occupant Risk


OIV=4.7m/s Pass

Occupant Risk


OIV = -2 m/s Pass

Occupant Risk


ORA = -9 G Pass

Occupant Risk


ORA = 6.7 G Pass

Vehicle Trajectory



Pass

Vehicle Trajectory



Pass


Conclusions

The objectives of this report were to evaluate the crash results of the ET-Plus end terminal installed with

a 31” rail system when tested to the NCHRP 350 Test Level 3 (TL-3) crash test conditions. Under this test

series, SWRI conducted the NCHRP 350 tests 3-30, 3-31, 3-32, and 3-33. The results are summarized in

the Table 10. My conclusion is that the test article successfully met the evaluation criteria for NCHRP

Report 350 tests 3-30, 3-31, 3-32, and 3-33.

Table 10. Test Results for Test 3-33 for ET-Plus installed with 31” rail system

Test NCHRP 350 Evaluation Criteria 3-30 3-31 3-32 3-33

Structural Adequacy


Pass Pass Pass Pass

Occupant Risk


Pass Pass Pass Pass

Occupant Risk


Pass Pass Pass Pass

Occupant Risk


Pass Pass Pass Pass

Occupant Risk


Pass Pass Pass Pass

Occupant Risk


Pass Pass Pass Pass

Occupant Risk


Pass Pass Pass Pass

Vehicle Trajectory


** Pass Pass Pass

Vehicle Trajectory


Pass Pass Pass Pass

** Vehicle spun out on traffic side of test article, and potentially into adjacent traffic lane. Note that

this evaluation criteria is preferred, but not required. Vehicle spinout is typical behavior for this type of

offset test.


References

Ferren J, “NCHRP Report 350 Test Report Compilation: Full-Scale Crash Evaluations of the ET-Plus End

Terminal with 4-inch Wide Guide Channel Installed with a Rail Height of 27 ¾ Inches – Test Level 3, Test

3-33, 3-31, 3-32, and 3-30”, SWRI Document Number 18.20887.03.100FR0, Issue 1 (January 23, 2015)

Ferren J, “NCHRP Report 350 Test Report Compilation: Full-Scale Crash Evaluations of the ET-Plus End

Terminal with 4-inch Wide Guide Channel Installed with a Rail Height of 31 Inches – Test Level 3, Test 3-

33, 3-31, 3-32, and 3-30”, SWRI Document Number 18.20887.05.100FR0, Issue 1 (February 17, 2015)


Appendix A

Evaluation of the Potential for Serious Occupant Injury in

SWRI Test ET31-30

The NCHRP 350 evaluation criterion D states that “Deformations of, or intrusions into, the occupant

compartment that could cause serious injuries should not be permitted”. This section analyzes the

potential for occupant injury due to intrusion of the test article into the occupant compartment in SWRI

test ET31-30.

The discussion below first describes the mechanical loading of the occupant and then assesses the

potential for serious injury from this loading. Because the dummy in the ET31-30 test was not

instrumented, my approach was to assess the potential for injury from 4 different perspectives:

a) Feasibility of Serious Lower Extremity using the Abbreviated Injury Scale

b) MASH Intrusion Criteria

c) IIHS Side Crash Structural Criteria

d) IIHS Lower Extremity Injury Criteria

Mechanical Loading of the Occupant During the ET31-30 test, the rail folded outward toward the traffic side of the system after impact.

Simultaneously, the car began to spin clockwise after impact. The folded rail struck the driver door

between the driver door forward hinge, and the leading edge of the driver seat. The impact drove the

door in as far as the steering wheel. There was no penetration of the door by the rail. Post-crash

measurements of intrusion showed that the folded rail impact with the door resulted in 6.75” of static

deformation of the door into the occupant compartment. From the videos and post-crash photos, there

did not appear to be any deformation of the B-pillar. The driver door became unlatched during the test

and bowed outward. This was likely the result of the force of the folded rail on the door forward of the

dummy torso directed inward combined with the loading from the occupant torso onto the door near

the B-pillar directed outward.

Examination of the video shows that the peak intrusion was between the driver door forward hinge, and

the leading edge of the driver seat. Prior to the rail-door impact, the clockwise spin of the vehicle

appears to have flung the torso of the belted driver against the door. The position of the legs was not

visible in the pre-crash portion of the video. Likewise, the position of the left arm was not visible in the

pre-crash portion of the video. However, the pre-crash photos shows that the left arm was positioned

at the side of the driver torso.

As part of this project, we conducted an analysis of the video of the crash test and estimated that the

folded rail struck the driver door at approximately 41 km/hr. The impact of the folded rail with the door

appeared to directly strike the distal end of the upper leg. The folded rail struck the door at the

approximate location of the steering wheel. Examination of the external videos shows that the top of


the folded rail at impact was at approximately the height of the seat pan. The location of impact and

the fact that the arms were initially at the side of the dummy suggests that the left arm was out of the

region of maximum intrusion. Likewise, the rail did not appear to directly engage either the torso or the

head of the dummy. As the dummy torso was in contact with the door at the time of impact and no

door intrusion was observed at the point of torso-door contact, my assumption is that the acceleration

experienced by the dummy torso was approximately the same as the vehicle. Because the lateral ORA

was well within the preferred range, there would not appear to be an unacceptable risk of serious torso

injury. The question of serious injury risk to the legs remains to be answered.

Are Serious Injuries of the Legs and Arms possible? Examination of the video shows that the intruding door directly struck the lower extremities. The

question is whether an impact to the lower or upper extremities can ever result in a serious injury.

NCHRP 350 does not precisely define what is meant by ‘serious injury’. In this study, my approach was

to use the Abbreviated Injury Scale (AIS).

The AIS is an injury coding system developed by the Association for the Advancement of Automotive

Medicine [AAAM, 2001]. AIS is a trauma-specific, anatomically-based coding scale that is widely used to

describe the type and severity of injuries arising from motor vehicle crashes. NHTSA uses AIS as the

injury severity foundation for both its regulatory and research programs. Each injury incurred by a

person or subject is coded on a six point scale which ranges from 1 for minor injuries to 6 for

unsurvivable injuries as shown in Table 11. The AIS system is based on the assessment of threat to life,

which was developed by a consensus of trauma surgeons. Note that under the AIS, a serious injury to

fatal injury is denoted by an AIS score of 3 or higher.

Table 11. Abbreviated Injury Scale

AIS Score Injury Severity

1 Minor

2 Moderate

3 Serious

4 Severe

5 Critical

6 Unsurvivable

The first aim was to determine whether the impact of the intruding rail/door with the legs could have

resulted in serious injury. Amputation of the leg above the knee would be scored as AIS 4, a severe

injury. However, without penetration of the rail through the door, amputation seems unlikely.

However, even without amputation, femur fractures are rated as a serious injury with an AIS score of

AIS=3. Amputation of the leg below the knee, unlikely in this test, has a score of AIS=3. Fractures of the

lower leg, i.e. the tibia and fibula, have a maximum of AIS = 2. My conclusion is that the risk of serious

injury cannot be discounted simply because the impact is to the legs. An AIS 3 femur fracture could

occur as a result of an impact to the upper legs and would be considered serious injury.


Injuries to the arms range from AIS=1 for minor lacerations and contusions, AIS=2 for a closed fracture,

to AIS=3 for open, displaced, or comminuted fractures of the bones of the upper arm, i.e. the humerus,

the ulna, and the radius. Amputation of the arm during a crash has an AIS score of 3. However, as the

rail did not penetrate through the door or window opening, amputation of the arm seems unlikely.

Note that AIS-90 (update 1998), the scale used here, scores an amputation of the arm at the same

severity as an open, displaced, or comminuted fracture of the upper arm. Although an amputation is

unlikely, a serious (AIS 3) upper arm fracture would be possible under direct lateral loading.

MASH Intrusion Criteria The newly developed MASH crash test procedures add additional evaluation criteria to better define

what intrusion is acceptable in roadside hardware crash tests. The MASH criteria acknowledge the fact

that injury risk is likely to be a strong function of the location of any intrusion. MASH also emphasizes

the need to differentiate between (1) penetration of the test article into the occupant compartment

which MASH states is unacceptable and (2) intrusion or deformation of the occupant compartment

under crash loading which may be acceptable within limits. Table 12 presents the limits on occupant

compartment intrusion under MASH:

Table 12. MASH Intrusion Limits

Deformation Area Intrusion limit (inches)

Notes

Roof 4.0

Windshield 3.0 No tear of plastic liner

Window No shattering of side window from direct contact with test article

Wheel/foot well and toe pan areas 9.0

Side front panel (forward of A-pillar) 12.0

Front side door area (above seat) 9.0

Front side door area (below seat) 12.0

Floor pan and transmission tunnel areas 12.0

Under the MASH Intrusion limits, it would appear at first glance that the ET31-30 max intrusion of 6.75”

would be acceptable. However, the MASH intrusion limits may not be applicable to the side impact

loading observed in the ET31-30 crash tests. Appendix A5.3 of the MASH procedure indicates that these

intrusion values were based upon the recommended guidelines developed by the Insurance Institute for

Highway Safety (IIHS) for evaluating structural performance of vehicles in offset frontal crash tests. The

IIHS frontal-offset crash tests primarily load the front of the vehicle structure along the longitudinal axis

of the vehicle. The door is not directly struck in IIHS frontal offset crash tests. In contrast, the folded

rail impact in Test ET31-30 primarily loaded the driver door along the lateral axis of the vehicle. The

MASH intrusion criteria do not appear to be applicable to the ET31-30 rail to door impact.

IIHS Side Crash Structural Rating The IIHS conducts side crashes which may be more relevant to the ET31-30 test than the frontal-offset

crashes referenced in MASH. The side crashes are conducted by impacting a 1500 kg movable

deformable barrier (MDB) at an angle of 90 degrees into the side of a stationary car at 50 km/hr (31.1


mph). Among other evaluation criteria, the IIHS scores the crash test outcomes with a structural rating.

The structural rating is based upon the post-crash position of the struck side B-pillar in relationship to

the centerline of the seat pan. Table 13 presents the IIHS side crash structural rating system:

Table 13. IIHS Side Crash Structural Rating Levels

Lateral distance between B-pillar (post-crash) and driver seat centerline (pre-crash)

Rating

>= 12.5” Good

>=5.0” Acceptable

>= 0” Marginal

Intrusion beyond seat centerline Poor

Examination of the video and post-crash photos in the ET31-30 test showed little to no deformation of

the B-pillar. Again, the IIHS structural criteria may not be the most relevant to the point loading of the

ET31-30 test. Although both the IIHS test and the ET31-30 test both engage the side of a car, they differ

in the area which was loaded. Because the IIHS MDB is 1.676 meters in width, it involves a broad

distributed loading ranging across essentially the entire side of the occupant compartment. In this

distributed loading, basing structural integrity upon the deformation of the B-pillar is appropriate. In

contrast, the folded rail impact in the ET31-30 loaded only a narrow area of the door forward of the

torso. Although such a narrow loading could produce injury, it would not be expected to deform the B-

pillar.

IIHS Side Crash Test Upper and Lower Extremity Injury Criteria

The IIHS side crash test described above also prescribes limits on the loads to an instrumented dummy

seated in the driver location. For the lower extremities, the IIHS test procedure defines the threshold

between poor and marginal performance at the distal end of the femur as a moment in the anterior-

posterior or lateral-medial axis of 356 N-m, and a lateral force on the distal end of the femur of 3.9 kN.

The threshold between good and acceptable performance at the distal end of the femur is defined as a

moment in the anterior-posterior or lateral-medial axis of 254 N-m, and a lateral force on the distal end

of the femur of 2.8 kN.

Because the ET31-30 dummy was not instrumented, my approach was instead to look for

measurements of these values in a comparable crash test in which the dummy had been instrumented.

NHTSA test 3444 conducted in August 2000 subjected a 1996 Geo Metro 3 door to a side impact by a

950-kg movable deformable barrier at 50 km/hr (MGA, 2000). Instrumented EuroSid-2 dummies were

seated in the driver and the left rear passenger positions.

The impact in the NHTSA test drove the door into the occupant compartment, striking the driver.

External door crush at the approximate position of the left upper leg was approximately 195 mm (7.6

inches). The electronic data for the femur channels was downloaded from the NHTSA Vehicle Crash

Test Database and filtered at 600 Hz. The peak lateral force on the distal end of the left femur was 1.7


kN. The peak bending moment of the left femur was 186 N-m. Both bending moment and peak lateral

force are within the IIHS good-acceptable region.

The IIHS side crash test described above prescribes limits on shoulder deflection. However, test 3444

did not measure shoulder deflection, but measured shoulder load instead. Regardless, the shoulder was

not directly impacted in the ET31-30 test. Hence, any shoulder measurements from test 3444 would not

be relevant to the ET31-30 test. Likewise, neither the humerus nor the lower arm were instrumented in

test 3444, and hence no measure of injury to these body regions could be assessed. But as noted above,

the left arm of the dummy, although flung away from the door on impact, did not appear to be in the

region of maximum intrusion which should reduce the potential for serious injury.

Although the NHTSA test is not identical to the ET31-30 door impact, the two are similar in several

respects. First, the Geo Metro in the NHTSA test is the same model used in the ET31-30 test. The

deformation at the location of the femur was also similar: the external door crush was 7.6” in the

NHTSA test vs. 6.75” intrusion in the ET31-30 test. Because the width of the door (typically 3-4”)

usually collapses to some extent before external impacts result in intrusion, my expectation is that the

external door crush to be somewhat higher than the intrusion for a similar level of intrusion. Finally,

the impact speed was similar. The impact speed in the NHTSA test was 50 km/hr. This is somewhat

higher, but of similar magnitude to the ET31-30 door impact speed which we estimated to be 41 km/hr

based on video analysis. There are also important differences between the two tests. Most notable is

that the ET31-30 test involved a narrow loading of the door by the folded rail, whereas the side

structure in the NHTSA test was subjected to a distributed loading across the A-pillar, door, and B-pillar.

Conclusion

Based on this analysis, my conclusion is that a driver exposed to the crash conditions of SWRI test ET31-

30 would have been unlikely to have been at risk of serious injury from the folded rail impact to the

driver door.

References

Association for the Advancement of Automotive Medicine (2001) The Abbreviated Injury Scale: 1990

Revision, Update 98.

MGA Research, ES-2 – Full Scale Vehcicle Tests Report No. 1, Testing for EU 96/27/EC European Side

Impact, 1996 Geo Metro 3 door, August 11, 2000 (Test V3444)

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